Heat-sensitive link for automatic fire apparatus.



A. B LAUV ELT. HEAT SENSITIVE L|N K FOR AUTOMATIC FIRE APPARATUS.

APPLICATION FILED JUNE IO. I9I5- Patented Oct. 3, 1917.

2 SHEET8-SHEET I-,

A. BLAU VELT. HEAT SENSITIVE LINK FOR AUTOMATIC F'IRE APPARATUS.

' APLlCATION FiLE-D JUNE 10. l9l5- 1,243,696.

Patented Oct. 23, 1917.

' 2 SHEETS-SHEET 2.

EEG. BLAUVEL'I, 0F OHIGAGO, 01S.

Specification of Letters Patent.

in: 'E-SSITIVE LDTK FOB AUTOMATIC? FIRE AP? 3* rammed Oct. 23, 1917.

Application filed June 10, 915. Serial 1%. 33,345.

To all whom it may concern: 7 7 Q Be it known that I, ALBERT BLAUVELT, a citizen of the United States, residin at Chicago, in the county of Cook and tate of Illinois, have invented certain new and useful Improvements in Heat-Sensitive Links for Automatic Fire Apparatus, of which the following is a specification.

My invention is applicable to all kinds of apparatus in which a part is to be released or moved after a certain temperature is attained in the surrounding medium or atmosphere) Examples of such devices which may be cited are sprinkler heads or automatic fire extinguishers which are attached to systems of piping under water pressure and controlled-by a valve releasedin some suitable manner after the critical temperaturehas been attained, fire alarms, electric or otherwise, which are-operated or permitted to operate when a certain temperature is attained and fire doors which are released automatically at like temperatures. The above are a few of the many devices in connection with which my invention may be used.

In each of them it is customary to em-- ploy a link formed of two parts soldered together by fusible metal and normally under tension and maintaining a normal condition of the apparatus. he fusible metal soldered joint is supposedly strlclpg enough to resist the tension on the,

while cold and until the temperature rises to a predetermined degree, which latter is chosen with reference to the heat which would be developed by fire in its initial stages in the apartment or building in which the apparatus is placed. When the critical temperature is exceeded, however, the solder becomes softened or fused releasing the sections'of the link from each other. In the case of a sprinkler head the link is used to maintain a valve closed. Ordinarily one or more resilient members force the valve to its seat and are maintained under stress by the link. In the case of an alarm apparatus the link may serve to hold open the switch or connector in an electric circuit; and in case of a fire door the link may serve to hold the door open against the tension of a spring or the like. Examples of the use of heat sensitive or fusible links are to be seenin patents to Hibbard Nos. 531,120 of December 18, 1894, 733,646 of July 14, 1903, and

922,140 of May 18, 1909. In each of these patents it w1ll be noted that the valve is maintained closed by a mechanical brace or braces which are maintained under stress by links of the character referred to above. These links consists in overlapping plates which are transversely grooved and soldered together. The "diliiculty with constructions of this character, however, arises from the fact that thestrain which the link will-bear is dependent upon the adhesive and tensile strength of the soldered joint and is therefore not only much less, in any construction of practicable size, than is desirable for many purposes as for example in a sprinkler where highwater pressure 1s available, but is also erratic because of the difliculty in getting uniform soldered joints. The fusible alloys which are employed for this purpose are largely non-homogeneous and the com-- ponent metals are inclined to further segregate when reheated for the purpose of making .the joint. Irregularities in fluxing, formation of bubbles, and oxidation, either at the time of forming the joint or subsequently thereto, are among other causes which render soldered joints of this character unreliable. So well known is the unreliability of sprinkler heads-due to the variabilityof the fusible joints that insurance is frequently taken out against flooding where sprinklers of this character are employed.

It is the object of my invention to obviate the objections recited above by providing a joint'for links of this character which is fully as sensitive as the soldered joint just referred to but which will be. independent of the tensile and adhesive strength of the fusible metal employed and not subject to the irregularities to which attention'has been called. In my improved construction the separable members of the link are main- .tained in locked engagement by a clamp,

The

ice

eral modifications are shown for purposes of exemplificatlon only, however, and the scope of the lnvent-ion 1s descrlbed 1n the following claims in which I have en-' For the purpose of this invention the par ticular character of the parts maintained in relative position by the links is immaterial and they are therefore only shown fragmentarily in the drawings. In Fig. 1 the link is shown as connecting the ends of a pair of levers; in Figs. 2*, 3 4 it is shown as connecting a pair of rods and in Figs. 5* and 6 as connecting a pair of wires.

An inspection of the several figures will show that they have in common a clamp by which the link members are normally maintained in interlocked position but the jaws of which are adapted to separate sufficiently at the critical temperature to release the members of the link.. The clamp consists of a bolt 7 which is threaded at one end and provided with a nut 8 and at its other end formed with a head or plunger 9. A cup or capsule 10 has a bore which loosely fits the head or plunger 9 and a hole 11' in its bottom through which the bolt 7 extends. The capsule 10 is packed with fusible material 12 preferably fusible metal which is granulated and filled into the capsule between the bottom of the latter and the head or plunger 9. Any of the well-known fusible alloys may be employed .for the purpose, though the material should be chosen with reference to the temperature at which it is de sired to yield and preferably the metal is granulated and thoroughly mixed, cold, so that any irregularities due to segregation of the metal components thereof may be distributed. In order that there may be no oxidation or corrosion of the granular metal the device is given a thin coating of wax or similar air-excluding material which because of the smallness of the opening in the bottom of the capsule and the interval between the plunger or head 9 and the cup completely seals the fusible material. Preferably washers 13, 14, are interposed between the members of the link and the head and cup respectively of the clamp.

The novelty of my invention resides in the construction just described and irrespective of the form of link to which it is apend as at 17, 18, to interlock and afford a extend beyond the same central passage for the bolt 7 of the clamp, and at the other end provided with holes 19, 20, through which the levers or other members 21, 22, to be maintained in fixed relation are passed. When the temperature rises sufficiently to soften the fusible metal in the cup or capsule, the tension of the levers 21, 22, which exerts a camming action between the link members, forces apart the nut and capsule of the clamp whereby the fusible metal is forced around the plunger or through the opening in the base of the capsule, thus permitting the latter to move outward and separate a suificient distance from the nut to disengage.

In Figs/2, 2 2 the .rods 23, 24, are maintained in normal relation by link members 25, 26, which are substantially pivoted upon the rod 23, embrace the rod 24 and where they are nested together by transverse corrugations at 27, The ends of the link members are slotted to receive the bolt of the heat sensitive clamp. When the latter yields to heat the rods 23, 24, tend to separate and throw the link members into the position shown in Fig. 2

The construction shown in Figs. 3, 3 3 is very similar to that just described but the link 28 is integral and of spring metal, the ends 29, 30 being brought together about the rod 31 and the clamp bolt 7 extending through openings 32, 33 in the link. As the fusible metal softens, the link yields to the pressure tending to separate the rods 31, 34. In the form of link shown in Figs. 4, 4 4 the link members 35, 36, are threaded upon a rod 37 at one end and at the other embrace a rod 38 perpendicular to rod -37. The clamp extends through holes 39, 40, in the link members and normally serves to maintain them closed yielding as heretofore described under rising temperature.

In the construction shown in Figs. 5, 5

permit the link members to 5 a lozenge-shaped block 41 is threaded them and the inclined face of the block the under the conditions referred to above,

the fusible metal of the clamp yields to the.

heat the link members 46, 47, are permitted to separate in the obvious manner shown in hus it will be seen that in each form of link the parts are held in engagement by the heat sensitive clamp and'germitted to separate under'the stram to w ch they are subjected when the temperature rises sufficiently to substantially soften the fusible metal. The se aration of the link-members depends as in t e former construction on the softening or fusin oint of a fusible metal but the strength 0 t e link at ,ordinary temperatures is absolutely independent of the tensile and adhesive strength of the fusible metal. The strength of the clam under normal conditions depends upon e compressive strength of the fusible metal which, present in thedevice by which the pressure is evenly applied and distributed to the granulated metal, far exceeds the tensile strength of said metal. As heretofore stated I claim no novelty in the particular form of the link and anfy of those shown may be applied to any 0 the uses as for example for maintaining a valve to its seat, for restraining the operation of an electnc or other fire alarm, or'for normally maintaining a fire door 0 en.

Pre erably the link is assembled by first filling the capsule about the bolt with granulated metal, which if desired may be simply poured in, then assembling the link members and putting the bolt with the capsule thereon in proper position and then screwing it t upon the b0 e nut until it firmly clamps the link sections between it and the capsule. The nut permits a ready adjustment of the parts to varying forms of links.

I claim:

1. A heat sensitive clamp for the purpose comprising a tensile member, a pair of abutments thereon, a receptacle movable longitudinally of the tensile member and a body of heat sensitive material loosely interposed between one of said abutments and said receptacle and a pair of elements engaged between the other of said abutvments and said receptacle and held thereby from movement relative to each other.

2. A heat sensitive device for the purpose described comprising a bolt, a pair of heads on the bolt, a receptacle surrounding the bolt and one of said heads and amass of heat sensitive material loosely interposed between said head and said receptacle and maintaining the receptacle and the head within the same in normal relation and a pair of elements engaged between the other of said abutments and said receptacle and held thereby from movement relative to each other.

3.111 a device of the class described, a bolt, -a head on the belt, a. receptacle surrounding said head and bolt, a body of insible metal loosely interposed between said head and receptacle and engaged by said head, a nut on the bolt and a pair of. elements engaged between said nut and receptacle and held from relative movement thereby.

4. In a device at the class described, a

bolt having a head thereon, a receptacle movable longitudinally of the bolt, a body of heat-sensitive material within the receptacle and maintained therein by the head of the bolt, a nut on the bolt, and a'pair of elements engaged between said nut and receptacle and eld from relative movement thereby. v

5. In a device of the bolt, a head thereon, a receptacle longitudinally movable upon the bolt, a mass ofheat sensltive material loosely inclosed by said receptacle and head, a nut adjustable on the bolt, and a pair of elements engaged between said nut and receptacle and held from relative movement thereby.

6. In a device of the class described, a link comprising a pair of relatively movable members, means for maintaining said members in relatively fixed position com.-- prising a bolt havinga head thereon, a capsule containing heat sensitive material 'class described, a I

prising a bolt extending through said passages, opposite abutments on said bolt, and a receptacle containing heat sensitive material surrounding said bolt and one of said a'butments.

8. In a device-of the class described, a bolt having an abutment at one end and a head at the other, a rece tacle mounted to slide on said bolt and em racing said head, a body of granulated fusible metal within said receptacle upon which said head bears,

said receptacle forming a second abutment.

9; In a device of the class described, a bolt having a. head formed thereon at one end and screw-threaded at the other, 'a nut on the screw-threaded end, a receptacle embracing the bolt and containing a mass'of granulated metal, said head substantially closing the end of said receptacle.

10. In a device of the class described, a pair of members under stress tending to move them away from each other, but having mutually engaging surfaces transverse to the line of stress, means for preventing lateral movement of the members relative to each other, comprising a bolt arranged transverse .to the line of stress and an abutment and a head on the bolt, an element movable longitudinally of the bolt, and a mass of heat sensitive material under compression between said element and head whereby lateral movement of said members relative to each other is normally prevented.

11. In a device of the class described, a bolt having an abutment on one end thereofv and a head on theother, a receptacle e mbracing the bolt and having an openin in the bottom thereof through which said olt passes, a mass of heat sensitive material in the receptacle, the head ofthe bolt being ,ing

member,

maaeeo larger than the opening in the receptacle pair of abutments thereon, an element havan opening closely fitting the tensile but permitting the free longitudinal movement thereof and a body of heat sensitive material interposed between one of-saidabutrnents andsaid elemeilt'l"' ALBERT BLAUVELT. WitIlGGSSGS: no. L. W. Goonwimm.

J. R. GATHERCOAL. 

